IOS4: AVFoundation: how to get raw footage from a movie

Question

How can i access the raw footage from movies taken with my camera, so i can edit or transform the raw footage ( eg: make it black/white ).

I know that you can load a mov with AVAsset make a composition with different AVAsset's and then export it to a new movie, but how do i access so i can edit the movie.

Answer 1

I don't know the whole process, but I know some:

You might need to use AV Foundation Framework and perhaps Core Video Framework to process individual frames. You will probably use AVWriter:

AVAssetWriter *videoWriter = [[AVAssetWriter alloc] initWithURL:
                              [NSURL fileURLWithPath:path]
                                            fileType:AVFileTypeQuickTimeMovie
                                               error:&error];

You can maintain a pixel buffer using AVFoundation or CV, and then write it like (this example is for CV):

[pixelBufferAdaptor appendPixelBuffer:buffer withPresentationTime:kCMTimeZero];

To get frames, AVAssetStillImageGenerator isn't really sufficient.

Alternatively, There may be a filter or instruction that can be used with AVVideoMutableComposition, AVMutableComposition, or AVAssetExportSession.

If you have made progress since you asked in August, please post as I'm interested!